“Pre-approved” really doesn’t mean pre-approved. It really means, “conditionally approved.” When you sign the application and send it in, you are giving the issuer permission to pull your credit reports and your scores. If you don’t meet their qualifications, they can deny you or approve your application but for a much lower credit limit than was offered in their mail. It’s the prototypical “bait and switch” game, especially if you have poor credit.